When a specimen is observed by a transmission electron microscope, a specimen to be observed is spread by use of a dispersion medium, such as water and an alcohol on a plastic support film such as a collodion film.
Conventional pretreatment methods for a specimen to be subjected to observation and specimen holding methods are as follows. For example, as shown in Patent Document 1, to observe a scanned electron microscopic image in a wet environment, there is a method of providing a partition to a specimen holding unit to prevent breakage of the specimen and controlling application of pressure. Furthermore, as shown in Patent Document 2, in a process of reducing the thickness of a powder specimen by a FIB process, there is a method of providing a recess in a plate-form specimen-holding substrate, thereby reducing the amount of embedding agent for holding the specimen and reducing the FIB process time. Moreover, as shown in Patent Document 3, when a powder specimen is observed by a transmission electron microscope, there is a method of sprinkling the powder specimen by means of vibration of a vibrator such that the specimen is sufficiently dispersed and deposited onto a collodion film.    [Patent Document 1] JP Patent Publication (Kohyo) No. 2005-529340A    [Patent Document 2] JP Patent Publication (Kokai) No. 11-30575A (1999)    [Patent Document 3] JP Patent Publication (Kokai) No. 49-103565A (1974)